feat(reverse_proxy): add Netcup DNS ACME challenge support and refactor Caddy setup

Signed-off-by: Tuan-Dat Tran <tuan-dat.tran@tudattr.dev>

roles/reverse_proxy/tasks/50_netcup_dns.yml

@@ -0,0 +1,14 @@
+---
+- name: Setup DNS on Netcup
+  community.general.netcup_dns:
+    api_key: "{{ reverse_proxy_netcup_api_key }}"
+    api_password: "{{ reverse_proxy_netcup_api_password }}"
+    customer_id: "{{ reverse_proxy_netcup_customer_id }}"
+    domain: "{{ domain }}"
+    name: "{{ service.name }}"
+    type: "A"
+    value: "{{ hostvars['docker-lb'].ansible_default_ipv4.address }}"
+  loop: "{{ services }}"
+  loop_control:
+    loop_var: service
+  delegate_to: localhost